1. Field of the Invention
This invention relates to a lubricant composition containing amine phosphate salts as a load carrying additive to provide lubricant compositions having balanced antiwear/extreme pressure and stability properties.
2. Description of the Related Art
Industrial oils such as gear oils which function under high contact pressures between moving parts typically contain a variety of additives to improve properties of the oil. Typical additives include viscosity improvers, extreme pressure agents, oxidation and corrosion inhibitors, pour point depressants, antiwear agents and foam inhibitors. PCT published application WO 87/07637 relates to a lubricating oil composition having improved high temperature stability which contains an amine phosphorus salt and the reaction product of a hydrocarbon-substituted succinic acid producing compound and an amine.
A problem encountered with commercial industrial oils which contain load-carrying additives is that corrosion and stability problems may develop over time which result in deposit formation, plugging of passages and filters, generation of acids, corrosion of metals, especially copper, and interference with lubrication. It would be desirable to have an industrial oil with excellent load carrying properties which is stable in prolonged use, especially at elevated temperatures and in the presence of water contamination.